Wireless-receiving system



Dec. 1 1925. 1,563,425

R. E. MARBURY WIRELESS nacmvme SYSTEM Filed June 17, 1920 ,r (I -m m 2; I:

22 j A A A l l l V V ,7 v V 2 WITNESSES: INVENTOR @W V 'Pa/OhEMa/"bz/ry BY Q -Vw- 1 ATTORNEY Patented Dec. 1, 1925.

UNITED STATES PATENT OFFHIE.

RALPH E. MARBURY, OF EDGEVIOOD PARK, PENNSYLVANIA, ASSIGNOR TO WEST- INGHOUSE ELECTRIC & MANUFACTURING CQMI'PANY, A. CORPORATION OF PENN- SYLVANIA.

WIRELESS RECEIVIN'G SYSTEM.

Application filed June 17, 1920. Serial No 389,601.

1 all whom it may concern:

Be it known that I, RALPH E. MARBURY, a citizen of the United States, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in liireless-Receiving Systems, of which the following is a specification.

My invention relates to wireless receiving systems, particularly as employed in wireless telegraphy, and its object is to devise a system of the character designated that shall permit the reception of relatively weak signals and which shall render them audible, even in the presence of violent disturbing impulses.

In the accompanying drawing, Fig. 1 is a diagrammatic view of one form of system embodying my invention, and Fig. 2 is a View similar to Fig. 1 and illustrative of a modification thereof somewhat better adapted for commercial use.

In the reception of wireless signals, it has been proposed to employ a local source of current of audible frequency and to control the flow of current from this source through a receiving device by means of the trigger action of an audion bulb or similar device.

' In accordance with the present invention, I secure the reception of signals in this general manner and, more particularly, as follows: A local source of current of audible frequency is connected in circuit with a device so adjusted as to establish parallel resonance, one of the resonating elements embodying the audion bulb or amplifying device, the effect of the parallel resonance being to substantiallyprevent the flow of currents of audible frequency through the receiving device. Upon the occurrence of an incombing signal, the impedance of the amplifying device is modified and, consequently, the condition of parallel resonance is partially or wholly destroyed. As a consequence, currents of audible frequency traverse the receiving device, and clear and easily readable signals are produced therein.

In a modification of my invention,the receiving apparatus is inserted in the secondary circuit of a transformer, the primary winding of which is tapped, as at the midpoint. An impedance device of definite value is in circuit with one-half the primary winding, and. a parallel resonance circuit of equivalent impedance is inserted in circuit with the other half of the primary winding so that, in the absence of incoming signals, the two halves of the primary winding buck each other, with cancellation in their inductive effects. Upon the occurrence of incoming signals, an abrupt change in the impedance of the parallel resonant circuit is effected, with radical disturbance of the magnetic balance previously obtained in the primary winding. Current flow is accordingly established in the receiving device, with the prcfduction of clear and easily readable signa s.

Referring to the accompanying drawing for a more detailed understanding of my invention, I show a receiving antenna at 5, connected to ground at 6 through the primary winding 7 of a transformer 8 having a secondary winding 9 connected to an amplifying bulb 10, of any desired form. The bulb is shown as having an incandescent cathode 11, a grid 12 and a plate anode 13, the grid 12 being placed between the other two electrodes in order to control the electron flow therebetween.

The plate circuit of the tube is connected through a winding 14 of a transformer 15 having a primary winding 16 connected in circuit with alternating-current source 17 of audible frequency, such for example, as 500 cycles. The winding 16 is shunted by a condenser 18, and a resistor 19 is inserted in circuit with the source 17, a receiver being shunted across a portion thereof. t

Under normal conditions. in the absence of incoming signals, there is a definite electron fiow through the tube 10, from which an equivalent impedance appears in circuit with the winding 14:, reflecting into the winding 16 and imparting a virtual impedance thereto. The condenser 18 is adjusted to a condition of parallel resonance with the virtual impedance of the winding 16, at the frequency of the source 17 The portion of the resistor 19 shunted by the receiver 20 constitutes two arms of a VVheatstone bridge. The remainder of the resistor 19 constitutes a third arm and the parallel circuit comprising winding 16 and condensor 18 is the fourth arm. The resistances are so chosen that, when this circuit is parallei-resonant, no current flows in the receiver.

It is well known that the characteristic cui ve of a parallel resonating circuit has an extremely 1 ronounced peak of little Width or, in other words, that an extremely slight diversion "from the frequency of true paral lel resonance largely destroys the impedance eliect and permits large current flow. Thus, the receipt of an incoming signal, with the attendant modulation of the potential of the grid 12, produces a more or'less marked disturbance of the virtual impedance of the coils l4 and 16, this disturbance being amply suflicient, however, to substantially destroy the condition of parallel resonance. During the receipt of incon'iing signals, therefore, current from the source 17 produces clear and powerful signals in the receiver 20.

The use of circuit, such as that shown in Fig. 1, is subject to a slight disadvantage in that only one-half of the energy of incominp; impulses is employed, with. attendant weakness of signalsand liability to the establishment of upper harl'nonics. Accordingly, in the system of Fig. 2, I show two amplifying bulbs 10 and 10', so connected as to an'iplifysignals of either polarity received in the secondary windings 9 and 9" of thecoupling transformers, the attendant flow of amplified alternating current taking place through the winding 14 of a transformer 15 having a primary winding 16, as before.

The receiving device 20, however, ather than being connected directly in circuit with the source '17, is connected in circuit with the secondary winding 21 of a transformer 22.11aving a primary winding 23 tapped, at its middle point, for connection to one terminal of the source 17. The left-han3d terminal of the primary winding v23 is c0nnected through a parallel resonant circuit 16-18, established as in Fig. 1, whereas the right-hand terminal of the primary winding is connected to the other terminal of the source 1'? throurjh an impedance-device 24.

Under normal conditions of operation, in the absence of incoming signals, the adjustment is such that the virtual impedance of the windingl6 establishes substantially parallel resonance with the-condenser 18, the equivalent impedance of the parallel resonant circuit being substantially equalled by that of the impedance device Thus, such current flow as takes place from the source 17 through the primary winding 23 is in opposite directions in the two branches thereof. with consequent opposition of magneto-motive forces and non-excitation of the secondary winding 21.

The receipt of an incoming; signal modifies the equivalentimpedanceof the winding 14: and, consequently, the virtual impedance of the winding 16, radically modifying the equivalent impedance of the parallel resonating path -1618 and destroying the condition of balance obtained in the winding Accordingly, working flux is established in 'the core of thetransformer 22, and clear and powerful signals are produced in the receiver 20 from the electromotive force generated in the winding 21.

In the foregoing description, I have explained my invention as adapted for the reception of the usual dots and dashes of tclcgraphlc communication in which the signals are rendered audible by means of an auXiliary audio-frequency source.

iyh t the frequency of the radiation forming the incoming signals, the frequency of the signals themselves, that is, of the interruptions forming; that energy into dots and dashes, or of other modulations forming 1 the energy into signals in other ways, is frequently below the limit of audition. Moreover, my invention is not limited, in its broadest aspects, to the particular form of detecting apparatus illustrated as a balanced bridge, since any other known or sub- SC! uentl r discovered s stem for detcctin or I .3 z:

utilizing the modulated auxiliary currents may be substituted without departing from the spirit of some features of my invention.

l-l hile I have illsutrated my invention in two of its preferred forms, it will be noted by those skilled in the art that it is not so restricted but is susceptible of various modifications and alterations without departing rent from said source traverses said recciving device, and means whereby, upon the rc ceipt-of incoming signals, said condition of parallel resonance is modified with the production of current flow through the receiving device.

2. The method of detecting wireless impulses in a receiving system wherein a receiving device is dynamically coupled with a source of currents of audible frequency through a parallel. resonant circuit which comprises largely destroying the condition of parallel resonance for the frequency of said source upon the receipt of an incoming signal.

3. Ina wireless receiving circuit, the coin- 1ination with a source of alternating currents of audible frequency, of a transformer .havingits primary winding in circuit therewith, a condenser arranged in shunt relation to said primary winding and adjustable to produce a condition of parallel resonam-e Hit) with the virtual impedance thereof at the frequency of said source, a receiving device dynamically associated with said circuit, a receiving antenna and an amplifying bulb connected thereto and having a plate circuit connected with the secondary winding of said transformer, whereby, upon receipt of incoming signals, the virtual impedance of said transformer primary winding is modified with the destruction of said condition of parallel resonance and the production of current flow through the receiving device.

l. In a wireless receiving circuit, the combination with a source of alternating currents of audible freouency of a receiving transformer having a split primary winding and having a secondary winding inserted in circuit with a receiving device, a fixed impedance device in circuit with one-half or said primary winding and said source, an impedance device resonant to said source in circuit with the other half of said primary winding. and electroresponsive means for causing said last named impedance device to change in its eifective value upon the receipt of incoming signals, the adjustment being such that, during the non-receipt of signals, the two halves of said primary winding magnetically neutralize each other, with the attendant non-energization of the receiving device, and the adjustment further being such that, upon the receipt of incoming sig nals, the magnetic balance previously ohtaining in the primary winding of the transformer is radically disturbed, with the production of an electroinotive force in the secondary winding thereof and of a clear and powerful signal in the receiving device.

5. In a wireless receiving circuit, the combination with a source of alternating currents of audible frequency, of an auxiliary transformer having a split primary winding and having a secondary winding in circuit with a receiving device, an impedance device of fixed value in circuit with one-half of said primary winding and with said source, a parallel resonant aggregate in circuit with the remaining half of said primary Winding and said source, said aggregate comprising the primary winding of a coupling transformer shunted by a condcnsance, the secondary winding of said coupling transformer being inserted in the plate circuit of an amplifying bulb, whereby the virtual impedance of the primary winding of said coupling transformer is subject to modification upon the receipt of incoming impulses, the adjustment being such that the current flows permitted by said fixed impedance device and by said parallel resonant aggregate, respectively, in the two halves of said primary winding during the non-receipt of signals substantially magnetically neutralize each other, and the adjustment further being such that, upon the receipt or" an incoming signal,

the alte'ation in the virtual impedance of the primary winding of said coupling transformer largely destroys the condition of resonance in said parallel resonant aggre gate, radically disturbing the condition of magnetic neutralization previously obtaining in the primary winding of said auxiliary transformer and permitting the energization of said receiving device.

6. The combination with an electron tube having a cathode, a co-operating anode and a co-operating space-current controlling element, of an alternating-current source, an input circuit including said controlling element, an output circuit including said anode, a tuned circuit including inductive and capacitive reactance means associated with said source, a telephone circuit energized from said source and tuned circuit, and means associated with said output circuit for varying the sharpness of tuning of said tuned circuit.

7. The combination with an electron tube having a cathode, a co-operating anode and a co-operating space-current controlling element, of an alternating-current source, an-

input circuit including said controlling ele ment, an output circuit including said anode, a circuit distinct from said input circuit and including inductive and capacitive reactance-means associated with said source and tuned to the frequency thereof, a telephone circuit energized from said source and tuned circuit, and means associated with said output circuit for varying the tuning oft said tuned circuit.

8. The combination with an electron tube having a cathode, a co-operating anode and a co-operating space-current controlling element, of an alternating-current source, an input circuit including said controlling element, an output circuit including said anode, a tuned circuit including inductive and capacitive reactance-rncans associated with said source, a telephone circuit energized from said source and tuned circuit, and means associated with said output circuit and automatically acting upon energization of said input circuit for altering the tuning of said tuned circuit.

9. The combination with an electron tube having a cathode, a co-operating anode and a co-operating space-current controlling elelOO ment, of an alternating-current source, an

input circuit including said controlling ele ment, an output circuit including said anode, a tuned circuit including inductive and capacitive reactance means associated with said source, a telephone circuit energized -from said source and tuned circuit, and means for energizing said output circuit with alternating current from said tuned circuit.

10. The combination with an electron tube 7 having a cathode, a co -operating anode and tilt) said reactance a co-operating space-cu rent controlling element, of an altcrnating-ciu'rent source, an input circuit including said controlling element, an output circuit including said anode, a tuned circuit including inductive and capacitive reaetance means associated with said source, means for coupling said output circuit to one of said reactance means, a balanced impedance device associated with said tuned circuit for deriving spaced points of normally negligible potential-difference, said balanced conditions being disturbed by changes in said output circuit, and a telephone receiver connected to be energized from said points of normally negligible potential-difference.

11. The combination with an alternatingcurrent source, of a tuned circuit including inductive and capacitive reactance means associated with said source, a telephone circuit energize-d from said source and tuned circuit, a pair of oppositely connected asymmetrical conductors connected in shunt-cir cuit relation to one of said reactance means, and electroresponsive means for varying the impedance of at least one of said asymmetrical conductors.

12. The combination with an alternating current source, of a tuned circuit including inductive and capacitive reactance means associated with said source, a pair of oppositely connected asymmetrical conductors connected in shunt-circuit relation to one of means, electro-responsive means for varying the impedance of at least one of said asymmetrical conductors, a balanced impedance device associated with said tuned circuit for deriving spaced points of normally negligible potential-diiference, said balanced conditions being disturbed by changes in said electro-responsive means, and a telephone receiver connected to be energized from said points of normally negligible potential-difference.

13. The combination with a pair of electron tubes each having a cathode, a co operating anode and a co-operating spacecurrent controlling element, of an alternating-current source, an input, circuit for energizing said controlling elements, a common output circuit having two terminals each connected to an anode of one tube and a cathode of the other, means for coupling said output circuit to said source, a balanced impedance device associated with said coupling means for deriving spaced points of normally negligible potentiabdifference, said balanced conditions being disturbed by changes in said output circuit, and a telephone receiver connected to be energized from said points of normally negligible potential-difference.

14. The combination With a pair of electron tubes each having a cathode, a cooperating anode and ,a co-operating spacecurrent controlling element, of an alternating-current source, an input circuit for energizing said controlling elements, a common output circuit having two terminals each connected to an anode of one tube and a cathode of the other, a tuned circuit including inductive and capacitive reactance ieans associated with said source and tuned to the frequency thereof, a telephone circuit energized from said source and tuned circuit, and means associated with said output circuit for altering the tuning of said tuned circuit.

15. The combination with a pair of electron tubes each having a cathode, a cooperating anode and a co-operating spacecurrent controlling element, of an alternating-current source, an input circuit for energizing said controlling elements, a common output circuit having two terminals each connected to an anode of one tube and a cathode of the other, a tuned circuit including inductive and capacitive reactance means associated with said source and tuned to the frequency thereof, a telephone circuit energized from said source and tuned circuit, and means for energizing said output circuit with alternating current supplied through said tuned circuit.

16. The con'ibination with a pair of electron tubes each having a cathode, a cooperating anode and a co-operating spacecurrentcontrolling element, of an alternating-current source, an input circuit for ener gizing said controlling elements, a common output circuit having two terminals each connected to an anode of one tube and a cathode of the other, a tuned circuit including inductive and capacitive reactance means associated with said source, means for coupling said output circuit to one of said reactance means, a balanced impedance device associated with said tuned circuit for deriving spaced points of normally negligible potential-difierence, said balanced conditions being disturbed by changes in said output circuit, and a telephone receiver con nected to be energized from said points of normally negligible potentialdifference.

17. The combination with a circuit carrying modulated signal currents, of a source of auxiliary alternating currents having a period which is short compared to the shortest signal element desired to be transmitted, a circuit including inductance and capacitance elements associated with said source and substantially tuned to the frequency thereof, means operative in accordanee'with the modulations of the signal currents for varying of said tuning, and a circuit responsive to the resultant modulations in said auxiliary alternating currents.

18. The combination with a circuit carry ing modulated signal currents, of a source of auxiliary alternating currents having a period which is short compared to the shortest signal element desired to be transmitted, a circuit substantially parallel-resonant to the frequency of said source including inductance and capacitance elements and associated with said source, means operative in accordance with the modulations ofthe signal currents for largely destroying the condition of parallel resonance, and a circuit responsive to the resultant modulations in said auxiliary alternating currents. V

19. The method of receiving radio signals by means of an energized network, including a parallel-resonant circuit and two pairs of conjugate conductors, which includes altering the effective impedance of one branch of said parallel-resonant circuit in accordance with the received signals, whereby the character of said circuit is changed from parallel-resonant and the character of said pairs of connections is changed from conjugate, and translating the resulting current in one of said pairs into perceptible signals.

20. The method of detecting electrical signals through the instrumentality 'of a normally parallel resonant circuit which is normally resonant to an auxiliary source of alternating currents having a period which is short compared to the shortest signal element desired to be transmitted, said method consisting in causing the condition of parallel resonance to be largely destroyed in accordance with the incoming signals.

21. The combination with an electron device having a main space-current path and a controlling element, of a circuit carrying modulated signal currents associated with said controlling element, a source of auxiliary alternating currents having a period which is short compared to the shortest signal element desired to be transmitted, a substantially resonant circuit associated with said source, and means responsive to the resultant modulations in the space current for varying the sharpness of tuning of said substantially resonant circuit.

22. The combination with a pair of elec tron devices each having a main asymmetrically conductive space-current path and a controlling element, of a circuit carrying modulated signal currents, means for similarly energizing both of said controlling elements from said circuit, a source of auxiliary alternating currents having a period which is short compared to the shortest signal ele ment desired to be transmitted, a circuit associated with said source and substantially resonant at the frequency thereof, and means for oppositely associating said asymmetrically conductive paths with said resonant circuit for varying the sharpness of tuning thereof.

23. The combination with an electron device having a main asymmetrically conductive space-current path and a controlling element, of a second electron device having an asymmetrically conductive space-current path, a circuit carrying modulated signal currents associated with said controlling element, a source of auxiliary alternating currents having a period which is short compared to the shortest signal element desired to be transmitted, a circuit associated with said source and substantially resonant at the frequency thereof and means for opposite-1y associating said asymmetrically conductive paths with said resonant circuit far varying the sharpness of tuning thereof.

In testimony whereof, I have hereunto subscribed my name this 14th day of June 1920.

RALPH MARBURY. 

